I recently asked it about Nix Flakes, which were very niche and bew during ChatGPTs Training. It was able to give me a reasonable answer in English, but if I first asked it in German, it couldn't do it. It could reasonably translate the english one though, after it generated that. Depending on what language you use to prompt it, you get very different answers, because it doesn't do the transfer of ideas and concepts between languages or more generally, disconnected bodies of text sources.

It is somewhat obvious if you know about the statistical nature of the models they use, but it's a great example of why these things don't KNOW things, they just regurgitate what they read in context before.